Introduce regression tests

tests/pytest/requirements.txt

@@ -0,0 +1,2 @@
+pytest
+redis

tests/pytest/test_dragonfly.py

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+
+import pytest
+import redis
+from threading import Thread
+
+
+
+@pytest.fixture
+def client():
+    pool = redis.ConnectionPool(decode_responses=True)
+    return redis.Redis(connection_pool=pool)
+
+
+class BLPopWorkerThread:
+    def __init__(self):
+        self.result = None
+
+    def async_blpop(self, client: redis.Redis):
+        self.result = None
+
+        def blpop_task(self, client):
+            self.result = client.blpop(
+                ['list1{t}', 'list2{t}', 'list2{t}', 'list1{t}'], 0.5)
+
+        result = Thread(target=blpop_task, args=(self, client))
+        result.start()
+        return result
+
+
+@pytest.mark.parametrize('execution_number', range(5))
+def test_blpop_multiple_keys(client, execution_number):
+    wt_blpop = BLPopWorkerThread()
+    thread = wt_blpop.async_blpop(client)
+    client.lpush('list1{t}', 'a')
+    thread.join(timeout=2)
+    assert not thread.is_alive()
+    assert wt_blpop.result[1] == 'a'
+
+    thread = wt_blpop.async_blpop(client)
+    client.lpush('list2{t}', 'b')
+    thread.join(timeout=2)
+    assert not thread.is_alive()
+    assert wt_blpop.result[1] == 'b'